Fuel supply system for direct injected system for engines

ABSTRACT

A number of embodiments of direct injected V-type outboard motors provided with a very effective fuel supply system wherein the number of components can be significantly reduced as well as the elimination of many of the flexible conduits normally employed. This also permits the fuel system to be assembled as a relatively unitary assembly that can be then affixed to the engine. The arrangement is such that purging of the system from vapors during shutdowns is easily accomplished and the system can be purged without complicated construction. Furthermore, the system can be pressure tested by an arrangement where the low pressure system can bypass the high pressure system when the engine is not operating so as to be pressurized for testing purposes. However, when the high pressure system operates, then the bypass line will be closed by the shunting valve arrangement The direct injection system permits operation with two cycle engines even under low load and speed conditions by using residual gasses to assist in fuel vaporization.

BACKGROUND OF THE INVENTION

This invention relates to a fuel supply system for direct injectionengines and more particularly to an improved fuel supply system for anoutboard motor incorporating a direct injection system.

As is well known, in all fields of engine design there is an increasingemphasis on obtaining more effective emission control, better fueleconomy and, at the same time, continued high or higher power output.This trend has resulted in the substitution of fuel injection systemsfor carburetors as the engine charge former. In order to obtain stillfurther improvements, direct fuel injection systems are beingconsidered. These systems inject fuel directly into the combustionchamber and thus have significant potential advantages.

In many applications, the incorporation of direct injection isrelatively straightforward. However, in connection with outboard motors,the very compact nature of the outboard motor renders this furthersophistication in engine design difficult to obtain. The problems inconnection with direct fuel injection systems for outboard motors isrelated primarily to the space that is.

These problems arise, in part because of the number of componentsrequired for fuel injection and the very nature of some of thesecomponents. For example, with manifold injection systems for outboardmotors, it has been the practice to provide a fuel injection system thatincludes at last the following components:

a low pressure fuel pump,

a high pressure fuel pump,

a pressure regulator,

a vapor separator, and

a fuel rail for delivering the fuel to the injectors.

The use of a vapor separator is required primarily because of theconfined space and the fact that fuel vapors or air in the fuel,conditions primarily resulting from heat, can cause erratic injectionand poor performance.

For the same reasons, it has also been the practice to position the highpressure fuel pump in the vapor separator so as to permit it beingcooled and to minimize the amount of heat that is generated in thesystem and to remove the heat from the fuel that is delivered to theinjectors. This also saves space. However, this necessitates the use ofan electrically operated fuel pump. Such pumps have has limited capacityin the pressure which they can generate.

With direct injection systems, however, the fuel must be injecteddirectly into the combustion chamber. This means that the pressure intowhich the fuel is injected is higher than with manifold injectionsystems wherein the pressure is at substantially atmospheric or evenbelow. Electric pumps are not totally capable of supplying such highpressures.

In order to supply the necessary pressures for a direct cylinderinjection, it has been proposed to employ a fuel supply system of thetype used with manifold injection systems. This is comprised of anengine driven pump which supplies fuel to a vapor separator in which theelectrically operated fuel pump is provided. However, fuel is suppliedfrom this pump to a mechanical pump that is driven off of the engine andwhich can generate higher pressures as required by the direct injectionsystem. This type of system can be quite effective.

However, it is also generally the practice to provide an arrangement inthe fuel system where the system can be pressurized to test it forleaks. In addition, it is desirable to have a system wherein the fuelpressure can be released from the system in order to facilitateservicing and/or disassembly without having the fuel spurt out of thesystem. Where pumps of the type employing both an electric high pressureand an even higher pressure mechanical pump, this an provide a verycomplicated arrangement since each must be provided with its own testingand bleeding system.

It is, therefore, a principle object of this invention to provide animproved fuel supply system for a direct injected internal combustionengine, and particularly one that is utilized in an outboard motorapplication.

It is a further object of this invention to provide an improved highpressure system wherein testing and pressure relief can be simplyaccomplished and the number of valves and fittings to achieve this aresubstantially reduced.

In one form of manifolding for supplying fuel to the fuel injectors ofan engine, there is provided a vertically extending fuel rail thatconnects to a series of vertically spaced fuel injectors. The fuel railextends vertically in an outboard motor because unlike normalapplications, the engine rotates with its crankshaft journaled about avertically extending axis. This means that the cylinders are spacedvertically from each other rather than horizontally with normal engineapplications.

It has been the practice to supply the fuel to the fuel rail at thelower end thereof and to provide a pressure relief valve at the upperend that relieves the pressure by bypassing the fuel back to the systemupstream of the pump. Although these arrangements have some advantages,it must be borne in mind that outboard motors may be used relativelyinfrequently with some time intervals between use.

Since it is desirable to reduce the pressure in the system when theengine is not running, this means that the fuel is frequently drained orrelieved from the fuel rail and other components during times when thesystem is not being used. Bleeding the air from the system for a startup after periods of no-use is quite difficult with the prior art type ofarrangements.

It is, therefore, a still further object of this invention to provide animproved fuel delivery system for an internal combustion engine having adirect injection system and particularly when utilized in connectionwith an outboard motor wherein the components are arranged so as toprovide a self-bleeding operation upon start up after a period ofnonuse.

It is a further object of this invention to provide an improved andsimplified fuel manifold and fuel supply system for an outboard motorhaving a direct fuel injection system.

SUMMARY OF THE INVENTION

A first feature of this invention is adapted to be employed in a fuelsupply system for a direct injected internal combustion engine. The fuelsupply system includes a fuel storage tank and a first pressure pump fordrawing fuel from the tank and elevating its pressure to a first level.A second higher pressure pump is in communication with the first pumpand is adapted to receive the fuel from the first pump and to elevateits pressure to a higher pressure for delivery to a direct cylinder fuelinjector. In accordance with this feature of the invention, a system isprovided for bypassing the fuel delivered by the first pump past thesecond pump so that the pressure systems of both pumps can be testedfrom a single location.

Another feature of the invention is adapted to be embodied in a fuelsupply system for supplying fuel to a direct injected outboard motorhaving a plurality of vertically spaced cylinders, each of which issupplied with fuel from a respective one of a plurality of verticallyspaced fuel injectors. A fuel supply system is provided that includes avertically extending fuel rail connected to the fuel injectors isprovided for supplying fuel to the injectors. The fuel supply system hasboth a pressure inlet port and a pressure return port formed at theupper end thereof, and which ports are disposed above the uppermost fuelinjector served by the fuel rail.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a multi-part view showing: in the lower right-hand portion, anoutboard motor embodying the invention; in the lower left-hand portion,a rear elevational view of the outboard motor with portions removed andother portions broken away and shown in section so as to more clearlyshow the construction of the engine; and in the upper view, a partiallyschematic cross sectional view of the engine of the outboard motor withits induction and fuel injection system shown in part schematically. TheECU for the motor links the three views together.

FIG. 2 is an enlarged cross-sectional view taken through a portion ofone of the cylinders of the engine of this embodiment and shows indetail the fuel injection spray pattern relative to the scavenging airflow and the residual charge.

FIG. 3 is a cross-sectional view taken along a plane that passes throughthe scavenge and exhaust ports and is generally perpendicular to theclaim of FIG. 2.

FIG. 4 is a top plan view of the power head showing the engine in solidlines and the protective cowling in phantom.

FIG. 5 is a view looking in the same direction as FIG. 5, but with theaccessories, including the high pressure fuel pump, removed and with theengine broken away and shown in section.

FIG. 6 is a side elevational view of the power head showing the enginein solid lines and the protective cowling in phantom, and is taken inthe direction of the arrow 6 in FIG. 4.

FIG. 7 is a rear elevational view of the engine and is taken generallyin the direction of the arrow 7 in FIG. 4.

FIG. 8 is an enlarged top plan view, looking in the same direction asFIG. 4, but shows only the high pressure pump and its association withthe main fuel delivery system.

FIG. 9 is a view looking in the same direction as FIG. 7 and shows thosecomponents of the fuel supply system illustrated in FIG. 8.

FIG. 10 is an enlarged top plan view showing the high pressure fuel pumpwith the drive pulley thereof being shown in phantom.

FIG. 11 is a view looking in the direction of the arrow 11 in FIG. 10and showing a part of the fuel pump drive and cooling system broken awayand shown in cross-section.

FIG. 12 is a top plan view showing the main fuel manifold.

FIG. 13 is a cross-sectional view taken along a plane perpendicular tothe plane of FIG. 12 and passing through the center of the main fuelmanifold.

FIG. 14 is a cross-sectional view taken along the line 14—14 of FIG. 12.

FIG. 15 is an elevational view showing the side of the main fuel railthat mounts to the fuel injectors.

FIG. 16 is a cross-sectional view taken through a plane perpendicular tothe plane of FIG. 15 and passing through the center of the fuel deliverypassage.

FIG. 17 is a cross-sectional view taken along the line 17—17 of FIG. 16.

FIG. 18 is an enlarged cross-sectional view showing one of theconnectors for connecting the main fuel manifold to one of the fuelrails.

FIG. 19 is a top plan view of the mounting bracket for the high pressurefuel injection pump.

FIG. 20 is a view of the mounting bracket looking in the direction ofthe arrow 20 in FIG. 19.

FIG. 21 is a view of the mounting bracket looking in the direction ofthe arrow 21 in FIG. 19.

FIG. 22 is a view, in part similar to the lower left hand side view ofFIG. 1, and shows a second embodiment of the invention.

FIG. 23 is a view, in part similar to the lower left hand view of FIG. 1and to FIG. 2, and shows a third embodiment of the invention.

FIG. 24 is a view, in part similar to the lower left hand view of FIG. 1and FIGS. 22 and 23, and shows a fourth embodiment of the invention.

FIG. 25 is a rear elevational view, in part similar to FIG. 7, and showsa fifth embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The general overall environment in which the invention is practiced andcertain details of the engine will be described initially by referenceto FIG. 1. In the lower right hand view of this figure, an outboardmotor constructed and operated in accordance with an embodiment of theinvention is depicted in side elevational view and is identifiedgenerally by the reference numeral 31.

The entire outboard motor 31 is not depicted in that the swivel bracketand clamping bracket that are associated with the drive shaft housing,indicated generally by the reference numeral 32, are not illustrated.This is because these components are well known in the art and thespecific method by which the outboard motor 31 is mounted to the transomof an associated watercraft is not necessary to permit those skilled inthe art to understand or practice the invention.

The outboard motor 31 includes a power head, indicated generally by thereference numeral 33, that is positioned above the drive shaft housing32 and which includes a powering internal combustion engine, indicatedgenerally by the reference numeral 34. This engine 34 is shown in moredetail in the remaining two views of this figure and will be describedshortly by reference thereto.

The power head 33 is completed by a protective cowling which includes amain cowling member 35. This main cowling member 35 is detachablyconnected to a lower tray portion which is also not shown in this figureand which encircles an upper portion of the drive shaft housing 32.

Positioned beneath the drive shaft housing 32 is a lower unit 36 inwhich a propeller 37, which forms the propulsion device for theassociated watercraft, is journaled.

As is typical with outboard motor practice, the engine 34 is supportedin the power head 33 so that its crankshaft 36 (see the upper view)rotates about a vertically extending axis. This is done so as tofacilitate connection of the crankshaft 36 to a drive shaft whichdepends into the drive shaft housing 32 and which drives the propeller37 through a conventional forward, neutral, reverse transmissioncontained in the lower unit 36.

The details of the construction of the outboard motor and the componentswhich are not illustrated may be considered to be conventional or of anytype known to those wishing to utilize the invention disclosed herein.Those skilled in the art can readily refer to any known constructionswith which to practice the invention.

Referring now in detail to the construction of the engine 34 still byprimary reference to FIG. 1, in the illustrated embodiment, the engine34 is of the V6 type and operates on a two stroke, crankcase compressionprinciple. Although the invention is described in conjunction with anengine having this cylinder number and cylinder configuration, it willbe readily apparent that the invention can be utilized with engineshaving other cylinder numbers and other cylinder configurations. Somefeatures of the invention, however, have particular utility inconnection with V-type engines.

Also, although the engine 34 will be described as operating on a twostroke principle, it will also be apparent to those skilled in the artthat certain facets of the invention can be employed in conjunction withfour stroke engine. In fact, some features of the invention also an beemployed with rotary type engines.

The engine 34 is comprised of a cylinder block 38 that is formed with apair of cylinder banks 39 and 41. Each of these cylinder banks is formedwith three vertically spaced, horizontally extending cylinder bores 42.Pistons 43 reciprocate in these cylinder bores 42. The pistons 43 are,in tun, connected to the upper or small ends of connecting rods 44. Thebig ends of these connecting rods are journaled on the throws of thecrankshaft 36 in a manner that is well known in this art.

The crankshaft 36 is journaled in a suitable manner for rotation withina crankcase chamber 45 that is formed in part by a crankcase member 46that is affixed to the cylinder block 38 in a suitable manner. As istypical with two cycle engines, the crankshaft 36 and crankcase chamber45 are formed with seals so that each section of the crankcase that isassociated with one of the cylinder bores 42 will be sealed from theothers. This type of construction is well known in the art.

A cylinder head assembly, indicated generally by the reference numeral47, is affixed to the end of each of the cylinder banks 39 and 41 thatare spaced from the crank case chamber 45. These cylinder headassemblies 47 are shown in more detail in FIG. 2 and are comprised of amain cylinder head member 48 that defines a plurality of recesses 49 inits lower face. Each of these recesses 49 cooperate with the respectivecylinder bore 42 and the head of the piston 43 to define the combustionchambers of the engine. When the pistons 43 are at their top dead centerposition, the cylinder head recesses 49 form the major portion of thecombustion chamber. For that reason, the reference numeral 49 will beused, at times, to identify the combustion chamber per se.

A cylinder head cover member 50 completes the cylinder head assembly.The cylinder head members 48 and 50 are affixed to each other and to therespective cylinder banks 39 and 41 in a suitable, known manner.

Referring again primarily to FIG. 1, an air induction system, indicatedgenerally by the reference numeral 51 is provided for delivering an aircharge to the sections of the crankcase chamber 46 associated with eachof the cylinder bores 42. This communication is via an intake port 52formed in the crankcase member 46 and registering with each suchcrankcase chamber section.

The induction system 51 includes an air silencing and inlet device,shown schematically in this figure and indicated by the referencenumeral 53. The actual construction of this air line device appearspartially in FIGS. 4 and 6. In actual physical location, this device 53is contained within the protective cowling at the forward end thereofand has a rearwardly facing air inlet opening 54 through which air isinducted. Air is admitted into the interior of the protective cowling ina known manner, and this is primarily through a pair of rearwardlypositioned air inlet openings that appear only in phantom in FIG. 6 ofthe drawings where they are identified at Ai and have a construction asis generally well known in the art.

Referring again back to FIG. 1, the air inlet device 53 supplies theinducted air to a plurality of throttle bodies 55, each of which has athrottle valve 56 provided therein. These throttle valves 56 aresupported on throttle valve shafts. These throttle valve shafts arelinked to each other for simultaneous opening and closing of thethrottle valves 56 in a manner that is well known in this art.

As is also typical in two cycle engine practice, the intake ports 52have provided in them reed-type check valves 57. These check valvespermit the air to flow into the sections of the crankcase chamber 45when the pistons 43 are moving upwardly in their respective cylinderbores. However, as the pistons move downwardly, the charge will becompressed in the sections of the crankcase chamber 45. At that time,the reed type check valve 57 will close so as to permit the charge to becompressed.

The charge which is compressed in the sections of the crankcase chamber45 is then transferred to the combustion chambers 49 through ascavenging system which appears best in FIGS. 2 and 3. This scavengingsystem is of the Schnurl type and includes a pair of main scavengepassages 58 that are positioned on diametrically opposite sides of aplane L containing the axis A of the respective cylinder bore 42. Thesemain scavenge passages 58 terminate in main scavenge ports 59 so as todirect a scavenging air flow as indicated by the arrows S in FIGS. 2 and3.

In addition, an auxiliary scavenge passage 61 is formed between the mainscavenge passages 58 and terminates in an auxiliary scavenging port 62which also provides scavenging air flow indicated by the arrows S. Thus,during the scavenging stroke, the intake charge will be referred to thecombustion chambers 49 for further compression as the pistons 43 moveupwardly from their bottom dead center position so as to close thescavenge ports 59 and 63 and further compress the charge.

Continuing to refer primarily to FIGS. 2 and 3, a spark plug 64 ismounted in the cylinder head assembly 47 for each cylinder bore and hasits respective spark gap 65 disposed substantially on the cylinder boreaxis A. The spark plug 64 is fired under the control of an ECU, shownschematically in FIG. 1 and identified by the reference numeral 66. ThisECU receives certain signals, as will be described, for controlling thetime of firing of the spark plugs 64 in accordance with any desiredcontrol strategy.

The spark plugs 64 fire a fuel air charge that is formed by mixing fueldirectly with the intake air via a fuel injector, indicated generally bythe reference numeral 67. The fuel injectors 67 are electricallyoperated and mounted directly in the cylinder head in a specificlocation, as will be described, so as to provide optimum fuelvaporization under all running conditions.

Fuel is supplied to the fuel injectors 67 by a fuel supply system,indicated generally by the reference numeral 68 and which will bedescribed first by reference to FIG. 1 and particularly the upper andlower left hand portions thereof.

The fuel supply system 68 is comprised of a main fuel supply tank 69that is provided in the hull of the watercraft with which the outboardmotor 31 is associated. Fuel is drawn from this tank 69 through aconduit 71 by means of a plurality of low pressure pumps 72. These lowpressure pumps 72 may, for example, be operated by the variations inpressure in the sections of the crankcase chamber 45, and thus provide arelatively low pressure.

A quick disconnect coupling is provided in the conduit 71 and also afuel filter 73 is positioned in this conduit at an appropriate location.Specific locations for these components are shown in later, moredetailed views.

From the low pressure pump 72, fuel is supplied to a vapor separator 74which is mounted, in a manner which will be described later, on theengine or within the protective cowling at an appropriate location. Thisfuel is supplied through a line 75. At the vapor separator end of theline 75, there is provided a float valve that is operated by a float 76so as to maintain a uniform level of fuel in the vapor separator 74.

A higher pressure, electric fuel pump 77 is provided in the vaporseparator 74 and pressurizes fuel that is delivered through a fuelsupply line 78 to a high pressure pumping apparatus, indicated generallyby the reference numeral 79. A low pressure regulator 81 is positionedin the line 78 at the vapor separator 74 and limits the pressure that isdelivered to the high pressure pump 79 by dumping the fuel back to thevapor separator 74.

The high pressure fuel delivery system 79 includes a high pressure pump82 that has a construction which will be described in more detail laterby reference to FIG. 11. It includes a pump drive shaft to which adriving pulley 83 is affixed. This driving pulley 83 is driven from apulley, to be described, mounted on the crankshaft 36 by means of adrive belt 84.

Fuel is supplied from the high pressure pump 82 to a main fuel manifold85 that is mounted on the engine and which has a construction which willbe described in more detail later. This will be done by primaryreference to FIGS. 7-9 and 12-14. The main fuel manifold 85, in turn,delivers fuel to a pair of vertically extending fuel rails 86. Thisconnection and the manner of delivery of fuel will be described later byparticular reference to FIGS. 15-18. The fuel rails 86 deliver fuel tothe fuel injectors 67 in a manner which will be described later bydetailed reference to FIG. 2.

The pressure in the high pressure delivery system 79 is regulated by ahigh pressure regulator 87 which dumps fuel back to the vapor separator74 through a pressure relief line 88 in which a fuel heat exchanger orcooler 89 is provided.

Referring again primarily to FIGS. 1-3, after the fuel charge has beenformed in the combustion chambers 49 by the injection of fuel from thefuel injectors 67, the charge is fired by firing the spark plugs 64. Thestrategy by which the injection tiring and duration is controlled by theECU 66, as well as the control for the timing of firing of the sparkplug 64 will be described in more detail shortly.

Once the charge burns and expands, the pistons 43 will be drivendownwardly in the cylinder bores until the pistons reach a positionindicated at 43 e in FIG. 2. At this time, an exhaust port 91 will beuncovered so as to open the communication with an exhaust passage 92formed in the cylinder block 38. It should be noted that the exhaustport 91 and exhaust passage 92 are formed diametrically opposite theauxiliary scavenge passage 61 and its scavenge port 63. However, theexhaust port 91 opens earlier and closes later than all of the scavengeports 59 and 63.

The exhaust gases flow through the exhaust passages 92 to collectorsections 93 of respective exhaust manifolds that are formed within thecylinder block 38 in a manner to be described in more detail later byreference to FIG. 5. These exhaust manifold collector sections 93communicate with exhaust passages formed in an exhaust guide plate 94 onwhich the engine 34 is mounted, as clearly seen in the lower left handview of FIG. 1.

A pair of exhaust pipes 95 depend from these exhaust guide exhaustpassages into an expansion chamber 96 formed in the drive shaft housing32. From this expansion chamber 96, the exhaust gases are discharged tothe atmosphere through a suitable exhaust system. As is well known inoutboard motor practice, this may include an underwater, high speedexhaust gas discharge and an above the water, low speed exhaust gasdischarge. Since these types of systems are well known in the art, afurther description of them is not believed to be necessary to permitthose skilled in the art to practice the invention.

Although any type of desired control strategy can be employed forcontrolling the time and duration of fuel injection from the injector 67and timing of firing of the spark plug 64, it will be apparent from thefollowing description that there is some significance in injector timingto improve good fuel vaporization under difficult running conditions.This will be described in more detail later by particular reference toFIGS. 2 and 3. However, a general discussion of some engine conditionshat may be sensed and some other ambient conditions that can be sensedfor engine control will follow. It is to be understood, however, thatthose skilled in the art will readily understand how various controlstrategies can be employed in conjunction with the components of theinvention that will be described in more detail.

Preferably, the control for the fuel air ratio includes a feed backcontrol system. Thus, a combustion condition or oxygen sensor 97 isprovided that senses the in cylinder combustion conditions by sensingthe residual amount of oxygen in the combustion products at a time nearthe time when the exhaust port 91 is opened. This is accomplishedthrough a sensor port 97 p as seen in FIG. 5. This output and air fuelratio signal are indicated schematically at 98 to the ECU 66.

There is provided also associated with the crankshaft 36 a crank angleposition sensor which when measuring crank angle versus time and outputan engine speed signal, indicated schematically at 99. Engine load, asdetermined by throttle angle of the throttle valves 56, is sensed by athrottle position sensor which outputs a throttle position or loadsignal 101 to the ECU 66.

There is also provided a pressure sensor 102 in the line connected tothe pressure regulator 87. This pressure sensor 102 outputs the highpressure fuel signal to the ECU 66, which signal is indicatedschematically at 103. At other times than during normal engine running,the sensor 102 may be utilized for another purpose, as will be describedlater.

There also may be provided a trim angle sensor 104 (see the lower righthand side view of FIG. 1) which outputs a trim angle signal 105 to theECU 66.

The sensed conditions are merely some of those conditions which may besensed for engine control.

The ECU, as has been noted, outputs signals to the fuel injector 67 andspark plug 64 for their respective control. These control signals areindicated schematically in FIG. 1 at 106 and 107, respectively.

It has been noted that when the engine is shut off, it is desirable torelease the high pressure that may exist in the fuel supply system andspecifically in the main fuel manifold 85 and fuel rails 86. To thisend, there is provided an electrically operated pressure release valve108 that is mounted in a bypass line 109 that extends from the main fuelmanifold 85 back to the return line 87 bypassing the pressure regulator87. When this valve 108 is opened upon the cessation of engine operationvia a control signal 111 from the ECU 66, the fuel pressure in thesystem will be relieved by dumping fuel back to the vapor separator 74.

The mounting of the fuel injector 68 and its positioning and injectionstrategy in order to obtain good running, particularly under thedifficult low speed low load condition will now be described by primaryreferences to FIGS. 2 and 3. First, it will be noted that the maincylinder head member 48 is formed with an opening 112 that iscomplimentary and receives a main body portion 113 of the fuel injector67. At its lower end, the injector opening 112 receives a seal 114 thatsealingly engages the injector around its discharge nozzle portion 115.

A retainer member 116 has an opening 117 that cooperates with a shoulder118 formed on the injector body and secures the injector 68 to thecylinder head in this relationship. The nozzle portion 115 extends intoa smaller diameter opening 119 formed at the lower periphery of theopening 102 and is located in an area that is preferably disposed in arelatively narrow range above the exhaust port 91 as shown in FIG. 3.

The injector nozzle has a conical spray pattern indicated as an S inFIGS. 2 and 3 which preferably is disposed so that the fuel spray willpenetrate the combustion chamber and will come into contact withresidual exhaust gas patches R1, R2 and R3 that exist during low speedand low load running conditions when the piston 43 is moving toward topdead center position and after the scavenged ports 59 and 63 and theexhaust port 91 have closed. This is preferably at a relatively shortangle before top dead center position of the piston and something in therange of about 3 to 10 degrees of crank rotation before top dead center.

Under this running condition there is little time for the fuel tovaporize before the spark plug is fired. Thus by utilizing the heat ofthe residual gasses vaporization can be obtained to insure good andcomplete combustion. Thus, the injected spray will pass through theresidual exhaust gases which will still be highly. Thus, the residualheat of combustion will help in vaporizing the injected fuel for thenext firing cycle and thus will insure that a stoichiometric mixture ispresent at the gap of the spark plug 65 at the time of firing.

Under high speed high load conditions, fuel injection may be done atsomething more like 90° before top dead center so as to insure thesupply of adequate fuel for combustion.

Having thus described the general overall system, the high pressure fuelsupply system 79 will now be described in more detail by reference tothe remaining figures of this embodiment. It should be noted that thishigh pressure system 79 including the high pressure fuel pump 83, themain fuel manifold 85 and the fuel rails 86 are designed so as to beconnected substantially rigidly together as a unit. This facilitatesmounting on the engine and also reduces the number of flexible hoses,which can cause problems with leakage and wear.

The description of the components will begin with the overallconstruction of those components which are basically assembled togetherand initially by reference to FIGS. 6-11. As may be seen in thesefigures, a driving pulley 121 is affixed to the upper end of thecrankshaft 36 to drive the drive belt 84, as previously noted. As may bebest seen in FIG. 11, the high pressure pump assembly 83 is comprised oftwo major components. These comprise a transmission 122 and the pump andpump valving bodies, indicated generally by the reference numeral 123.

Continuing to refer primarily to FIG. 11, the transmission portion 122is comprised of a housing assembly that includes a main housing member124 in which a pump drive shaft 125 is journaled by means of a plainbearing 126 and a ball bearing 127. The ball bearing 127 is mounted inan end portion of the housing assembly 124 which is closed by a closureplate 128 so as to define a cooling jacket 129.

The cooling jacket 129 receives cooling water from an engine coolingjacket, indicated generally by the reference numeral 131 through aconduit 132. As is known in the marine field, the water for cooling isdrawn from the body of water in which the watercraft is operating andretuned thereto after having passed through the respective coolingjackets. A suitable return conduit (not shown) is also provided toreturn that cooling water that has been circulated through thewaterjacket 129.

Because the pump drive pulley 82 and drive belt 84 are in proximity tothe cowling air inlets Ai FIG. 4) the pump and drive will be cooled bythe air flow caused by their movement.

An input shaft 133 is journaled in the housing member 124 and has thedriving pulley 82 affixed to its upper end. A pair of intermeshing bevelgears 134 transmit the drive from the intake shaft 133 to the pump driveshaft 125. This type of transmission can generate some heat and thecooling jacket 124 and air flow previously referred to assists indissipating that heat and ensuring that the high pressure fuel pump 83and particularly the pumping unit 123 will be cooled so as to not heatthe fuel that is delivered to the injection system. This will ensureagainst vapor being generated in the fuel system.

The transmission housing 124 is connected by means of an intermediatemember 135 to a flange 136 of the main high pressure pump body 123 bymeans of threaded fasteners 137. The pump body has a nose piece throughwhich the pump shaft 138 extends so as to be coupled by a splinedcoupling or coupling of another type to the pump drive shaft 125.

These shafts rotate about a generally horizontally extending axisindicated at PL which extends transversely across the upper portion ofthe engine 34 in an area that is disposed above and partly dependinginto the valley formed between the cylinder banks 39 and 41.

The pump body, indicated generally by the reference numeral 141, isformed with a plurality of tapped openings to receive fasteners forattachment to a support plate and also to the main fuel manifold 85 in amanner which will be described shortly. As may be seen, the pump body141 is formed with an inlet opening 142 that is adapted to receive afitting connected to one end of the fluid conduit which has beenindicated schematically as 78 in FIG. 1. A pair of tapped openings 143permit attachment of this fitting so that fuel can be delivered to thehigh pressure pump.

A pump discharge fitting 144 is formed below this inlet fitting and ispositioned so as to be attached, in a manner to be described, directlyto the main fuel manifold 85 so as to limit the necessity for aseparate, external conduit. Tapped openings 145 receive fasteners forthis purpose.

In accordance with another feature that assists in minimizing the numberof external conduits required, the high pressure regulator 87 previouslyreferred to is actually built directly into the pump body 141. A smallL-shaped fitting member 146 (FIGS. 7 and 8) is attached to a pressuresensing inlet fitting 147 formed in the pump body 41 so as to transmitthe fluid pressure from the main fuel manifold 85 to the pressureregulator 87.

The return conduit 88 from the high pressure regulator 87 is connectedto a relief fitting opening 148 formed in the pump body 141 verticallyabove the pressure regulator inlet opening 147. Thus, the number ofexternal conduit is still further reduced by this arrangement thatincorporates the regulator 87 directly into the body 141 of the highpressure pump assembly 83. The vertical spacing of the various fittingsalso assist in the relief of air back toward the vapor separator 74 whenthe engine has shut down and is again started up.

The construction of the main fuel manifold 85 will now be described byprincipal reference to FIGS. 12-14. This main fuel manifold 85 iscomprised of a generally rectangular metal body member 151 that isformed with a through drilling 152. This drilling 152 is closed at itsouter ends by end plug 153.

The side of the body 151 is provided with a first fitting member,indicated at 154 and which is shown in most detail in FIG. 14. Thismember 154 has an opening 155 that is adapted to be received in fluidcommunication with the high pressure pump outlet fitting 144. Through aconnector of the type shown in FIG. 18 or only employing an O-ring sealtherebetween. Thus, no external conduit are required for thiscommunication. The fitting 154 has a cross drilling 156 that permits thehigh pressure fuel to communicate with the manifold passage or drilling152.

The upper surface of the manifold body 155 and the surface which extendstransversely to the surface in which the fitting 154 is receivedreceives a further fitting 156, which fitting has an opening 157 so asto couple to the L-shaped connector 156 to communicate the pressure inthe manifold passage 152 with the pressure regulator as aforenoted bythe same measures as used in the connection to the high pressure pumpoutlet 144.

At the ends of the manifold 151 and on the under surface thereof, thereare provided a pair of fittings 158 which have openings 159 so as toreceive a coupling to provide a connection to the fuel rails 86, as willbe described shortly by reference to FIG. 18.

The construction of the main fuel rails 86 will now be described byparticular reference to FIG. 15-17. Like the fuel manifold 85, the mainfuel rails 186 are formed from rectangular metal bodies 161. A drilledpassageway 162 extends vertically through these bodies from their upperends to their lower ends. The lower ends thereof are closed by a closureplug 163. The upper end is provided with a counterbored opening 164 thatreceives a coupling member as will be described later by reference toFIG. 18 which may be the same as the type coupling member employed toconnect the high pressure fuel pump outlet 144 with the inlet fitting155 of the main fuel manifold 85. These couplings cooperate with thefitting openings 159 of the main fuel manifold 85 as will also bedescribed.

In the area where each of the fuel injectors 67 of the respectivecylinder bank lie, the fuel rail body 161 is provided with a drilledpassageway 165 which penetrates far enough into the body 161 tointersect the drilling 162 without having to be plugged at its outerend. These drillings 165 receive elastic sleeves 166 having openings 167that are complementary to fuel nozzle portions 168 of the fuel injectors67 so as to deliver fuel to them as seen in FIG. 2.

Drilled openings 169 also extend through the fuel rail 86 and the body161 thereof to receive threaded fasteners 171 so as to affix the fuelrail 186 rigidly to the injector mounting elements 161 and, accordingly,to the cylinder head assemblies 47.

The couplings that are employed between the main fuel manifold 85 andthe fuel rails 86 as well as those which may be employed between thehigh pressure fuel pump 83 and the main fuel manifold 85 as well asbetween the fitting 146 and the pressure regulator portion of the highpressure fuel pump 83 will now be described by particular reference toFIG. 18.

FIG. 18 shows specifically the connection between the main fuel manifold85 and one of the fuel rails 86. There is provided a cylindricalcoupling member 172 that is provided with a central bore 173 and whichis also formed with a pair of seal receiving grooves 174 at its oppositeends. Each of these grooves 174 receives a respective O-ring 175 and anylon backup member 176 so as to provide a leak-tight connection betweenthese elements and one which does not require threaded fittings.

In order to hold the main fuel manifold 85 in position relative to thefuel rails 86, a structure as shown in FIG. 9 is employed. This iscomprised of an L-shaped bracket 177 that is abuttingly engaged with thesurfaces of the fuel manifold 85 and the fuel rails 86 and fixed to themby threaded fasteners 178. As a result, this provides a unitary assemblywhich will ensure that the components are held together in sealedrelationship without requiring threaded fittings or flexible conduits.

This entire assembly is then mounted on the mounting bracket shown inmost detail in FIGS. 19-21 and which is indicated generally by thereference numeral 179. This mounting bracket 179 may be formed from asuitable high strength lightweight material such as an aluminum oraluminum alloy.

This member has a horizontally extending surface 181 with a pair offorwardly extending tabbed portions 182 which define an opening betweenthem. The portion 181 is adapted to underlie the main fuel manifold 85.The main fuel manifold 85 is provided through openings 186 that areadapted to receive threaded fasteners 187 as seen in FIG. 9. Thesethreaded fasteners are threaded into tapped openings formed on mountingbosses 188 that extend upwardly from the mounting plate surface 181.

As best seen in FIG. 8, the high pressure fuel pump assembly 79 has onerearward opening and a pair of forward openings. One of these openingsoverlies a further boss 191 formed on the mounting plate portion 181.The other openings overlie a pair of openings 192 that are formed on theextending portions 182 of the mounting plate 179. Threaded fasteners 193pass through these openings so as to secure the high pressure pumpassembly 79 also to the mounting plate 179.

Finally, the mounting plate 179 has a depending rib 194 that is providedfor reinforcing purposes and which has a plurality of ribs 195 thatextend beneath the surface 181 to add rigidity in this area.

A pair of forwardly positioned aperture 196 are formed in theforwardmost portion of the mounting plate projections 182 and receivethreaded fasteners for fixing the mounting plate 182 to the uppersurfaces of the cylinder banks 39 and 41, respectively, so as to providea secure mount for the pump assembly and manifold on the engine.

Referring now primarily to FIGS. 5 and 7, the mounting for certain ofthe control elements including the ECU 66 will be described. As may beseen in this Figure, the valley between the cylinder bank is closed by aclosure plate 198 which also partially encloses the exhaust manifold inpart by the cylinder block. A further cover plate 199 encloses thisclosure plate 198 to form a water jacket 201 through which cooling watermay be passed so as to cool the exhaust system.

Mounted on the cover plate 199 by means that include elastic isolators202 is mounting board 203 which carries the ECU 66. In addition, asolenoid coil driver arrangement 204 may be mounted on the outer side ofthe ECU in this area. This solenoid coil driver arrangement drives thesolenoid associated with the fuel injector 86 for opening the valves. Inaddition, this assembly may be attached at its upper end to the mountingbracket 179 through threaded fasteners that pass through apertures 204(FIG. 20) formed in the flange portion 194 thereof.

The spark coils for firing the spark plug 64, are indicated by thereference numeral 205 and are mounted on the adjacent side of themounting plate 203 so as to minimize the length of wiring and makes theelectrical connections more secure.

It has been mentioned that there is a desire to be able to pressure testthe system. This is accomplished with utilization of only the singlepressure gauge 102 and is done by means of a check valve arrangement asbest shown in FIG. 1 and particularly the upper view thereof. It shouldbe noted that the conduit 78 leading from the high pressure electricfuel pump 77 to the higher pressure, mechanical fuel pump 83 includes abranch passage 206, which bypasses the inlet and outlet sides of thehigh pressure pump 83. This conduit 206 extends in essence between thepump inlet and outlet fittings 142 and 145 as shown in FIG. 11 and maybe located within the pump body 141.

A check valve 207 is provided in this bypass conduit 206 that permitsflow to pass around the high pressure pump 83. However, there isprovided a further check valve 208 in the outlet side of the highpressure pump 83 between it and the discharge of the conduit 206. Thisis also preferably located within the pump body 141.

Thus, when the high pressure pump 83 is operating, the check valve 208will open and force the check valve 207 closed so that no fluid pressurewill be lost. However, by stopping the engine and running the electricpump 77, the fluid will flow through the conduit 78 and bypass conduit206 to close the check valve 208 and provide a pressure signal at thesensor 102. This may be used to check the integrity of the lowerpressure fuel system.

During normal engine running, the pressure sensor 102 will indicate thatthe high pressure side is not leaking and thus, the system can be usedand checked with a single pressure tap. In the embodiment as thus fardescribed, the main fuel manifold 85 has extended transversely acrossthe upper surface of the fuel rails 86. FIG. 22 shows another embodimentin the invention which is the same as that already described except forthe relationship between the main fuel manifold 85 and the fuel rails86. For that reason, only this single view, which is a reduced scaleview similar to the lower left hand portion of FIG. 1, is believednecessary to permit those skilled in the art to practice the invention.In this embodiment, the main fuel manifold is shorter in length and isjoined to the fuel rails 86 through their sides rather than throughtheir upper ends.

FIG. 23 shows another embodiment wherein the manifolding arrangementsimilar to that utilized in FIG. 22 is employed. In this embodiment,however, a transfer manifold 251 having a construction like the earliermain fuel manifold 85 but which is not a main fuel manifold connects thebottom of the two fuel rails 86 as seen in FIG. 23. The high pressurefuel pump 83, therefore, delivers fuel to one of the fuel rails 86through its upper inlet fittings and the pressure regulator inlet isdispose at the upper end of the other fuel rail.

FIG. 24 shows another embodiment that differs from those alreadydescribed and in the manifolding arrangement. In this embodiment, fuelis supplied to a main fuel manifold 85 that is positioned at the lowerend of the construction between the lower ends of the fuel rails 86. Across manifold 261 is also provided between the upper ends of themanifolds. High pressure fuel is supplied to the main fuel manifold 85through a delivery manifold 262 which communicates directly with thehigh pressure fuel pump outlet.

FIG. 25 shows a final embodiment of this invention and in thisembodiment, the vapor separator 74 is mounted on the back of themounting plate for the control body.

Thus, from the foregoing description, it should be readily apparent thatthe described embodiment of the invention provides a very effective fuelsupply system for an outboard motor wherein the number of components canbe significantly reduced as well as the elimination of many of theflexible conduits normally employed. This also permits the fuel systemto be assembled as a relatively unitary assembly that can be thenaffixed to the engine. The arrangement is such that purging of thesystem from vapors during shutdowns is easily accomplished and thesystem can be purged without complicated construction. Furthermore, thesystem can be pressure tested by an arrangement where the low pressuresystem can bypass the high pressure system when the engine is notoperating so as to be pressurized for testing purposes. However, whenthe high pressure system operates, then the bypass line will be closedby the shunting valve arrangement as shown in FIG. 1.

Of course, the foregoing description is that of preferred embodiments ofthe invention. Various changes and modifications may be made withoutdeparting from the spirit and scope of the invention, as defined by theappended claims.

What is claimed is:
 1. A fuel supply system for a direct injectedinternal combustion engine, said fuel supply system including a fuelstorage tank, a first pressure pump for drawing fuel from said tank andelevating its pressure to a first level, a second higher pressure pump afirst conduit in communication with said first pump and adapted toreceive the fuel from said first pump and to deliver fuel from saidfirst pump to said second pump to elevate its pressure to a higherpressure for delivery through a second conduit to a direct cylinder fuelinjector, and a bypass system including a bypass conduit extending fromsaid first conduit to said second conduit a first check valve in saidsecond conduit for permitting flow from only said second pump to saidfuel injector, said bypass conduit intersecting said second conduitdownstream of said first check valve and a second check valve in saidbypass conduit for permitting flow through said bypass conduit only fromsaid first conduit to said second conduit said bypass system bypassingthe fuel delivered by said first pump past said second pump so that thepressure systems of both pumps can be tested from a single location andconstituting the sole communication for fuel from said fuel storage tankto said fuel injector.
 2. A fuel supply system as set forth in claim 1further including a pressure sensor downstream of the second pump and incommunication with the discharge of the bypass system.
 3. A fuel supplysystem as set forth in claim 2 wherein the pressure sensor is positioneddownstream of the second pump and in communication with the discharge ofthe bypass system at a point downstream of the junction between thefirst and second conduits so as to sense only the pressure of the pumpdeveloping the highest pressure.
 4. A fuel supply system as set forth inclaim 1 further including a relief conduit connecting the bypass systemwith an area of low pressure and a control valve for controlling theflow through said relief conduit for selectively depressurizing saidbypass system and the area upstream of the fuel injector.
 5. A fuelsupply system as set forth in claim 4 further including means foropening the control valve upon stopping of the engine.
 6. A fuel supplysystem as set forth in claim 5 further including a pressure sensordownstream of the second pump and in communication with the discharge ofthe bypass system.
 7. A fuel supply system as set forth in claim 3further including a pressure regulator for regulating the pressure ofthe fuel delivered to the fuel injector.
 8. A fuel supply system as setforth in claim 7 wherein the pressure regulator regulates pressure byreturning fuel to a point upstream of the high pressure pump.
 9. A fuelsupply system as set forth in claim 7 wherein the pressure regulatorregulates pressure by returning fuel to a point upstream of both of thepressure pumps.
 10. A fuel supply system as set forth in claim 7 whereinthe downstream end of the relief conduit communicates with the return ofthe pressure regulator.
 11. A fuel supply system as set forth in claim 1in combination with a direct injected, outboard motor having a pluralityof vertically spaced cylinders, each of which is supplied with fuel froma respective one of a plurality of vertically spaced fuel injectors. 12.A direct injected, outboard motor as set forth in claim 11 wherein thefuel supply system includes a vertically extending fuel rail connectedto the fuel injectors for supplying fuel to said injectors, said fuelsupply system having both a pressure inlet port communicating with thepressure side of the high pressure pump and a pressure return portformed at the upper end thereof, and which ports are disposed above theuppermost fuel infest served by the fuel rail.
 13. A fuel supply systemas set forth in claim 12 in combination with an outboard motor comprisedof a power head consisting of a multi-cylinder internal combustionengine and a surrounding protective cowling and a driveshaft housing andlower writ containing a propulsion device within said lower unitdepending from said power head, said engine being mounted within saidprotective cowling so that its crankshaft rotates about avertically-extending axis, said crankshaft being coupled to a driveshaft that depends into said driveshaft housing and lower unit fordriving said propulsion device, said engine being formed with a numberof combustion chambers, a plurality of fuel injectors each of whichinjects fuel directly into a respective one of said combustion chambers,and further including a high pressure fuel pump contained within saidprotective cowling and disposed at the upper end of said engine drivenoff the upper end of said crankshaft for delivering high pressure fuelto said fuel supply system.
 14. An outboard motor as set forth in claim13 wherein the engine is of the V-type and has a pair of cylinder bankseach containing at least one combustion chamber and wherein the cylinderbanks define a valley therebetween.
 15. An outboard motor as set forthin claim 14 wherein the high pressure pump is disposed above the valleybetween the cylinder banks.
 16. An outboard motor as set forth in claim15 wherein the high pressure pump delivers fuel to a main fuel manifoldof the fuel supply system.
 17. An outboard motor as set forth in claim16 wherein the main fuel manifold supplies fuel to a pair of fuel railseach associated with a respective one of the cylinder banks.
 18. Anoutboard motor as set forth in claim 17 wherein the engine is acrankcase compression, two-cycle, internal combustion engine.